Refrigeration compressors emit an unacceptable level of noise. Many attempts have been made to dampen, absorb or otherwise effectively eliminate such emitted noise. None of them have been completely satisfactory for all types of compressors and applications.
As the piston moves or rotates in the compression chamber of a rotary compressor the vane moves in and out of the chamber to maintain contact with the side of the piston. This causes varying amounts of vane surface to be exposed to the fluid in the chamber. Since the vane divides the chamber between a suction, or low pressure, side and a compression or high pressure, side a varying pressure differential is applied to the exposed portion of the vane. The net result is that the vane moves from side to side within the slot and repeatedly strikes the cylinder, even though the vane and slot are formed for a close sliding fit. These strikings cause vibrations which travel through the cylinder and are emitted from the compressor as noise.